Lining for ball mills



July 19, 1949. F. MCINTYRE LINING FOR BALL MILLS 3 Sheets-Sheet 1 FiledOct. l, 1945 I/IIIIIIIIIA INveNTa@ July i9, i949. F, MCINTYRE 2,476,505

LINING ,FOR BALL MILLS Filed oct. 1, 1945 s sheets-sheet 2llllllllllllll Isini F. MCINTYRE LINING FOR BALL MILLS 5 Sheets-Sheet 3Filed OCC. l, 1945 Patented July 19,A 1949 NUruTlso sTATes arrestsAminne Fon Bann Mitts- Frank McIntyre, London, England, assigner toWilkinson Rubber Linatex Limited, London,

England Application October 1, 1945",` Serial N of. 6195560 In GreatBritain October- 20, 1944 Ball mills, pebble mills and like machines foruse in grinding ores and ceramic and other materials have a rotary'metal tumbler drurn and. it' has been proposed to line the drums of suchmachines with rubber for the purpose of protecting' the same againstabrasion by the contents of the drum and of preventing metalliccontamination of the contents of the' drum.

Effective bonding and/cr anchorage of the rubber lining to the metaldrum has however been dihicult to achieve because of the tremendousshearing forces to which the lining is subjected in use. Alsodifficulties have'ari'sen due to fatigue or breaking away of the rubberwhere it contacts with and is secured to the rigid metal surface.

rThe object of this inventionv is to provide a more effective form ofrubber lining for the metal drums of machines of the above characterthan those at present in use.

The lining according to the invention comprises a number of rubber ringsmounted in axial compression on longitudinally extending rods attachedat their ends to end plates or rings by which the lining is held inposition in the drum. rlhe rods and end plates or rings are preferablyof steel or other metal, and the rods are preferably of circularsection.

The rubber, being mounted in axial compression, is better able to resistabrasion than is a lining of rubber bonded to the'drum. Fatigue of therubber is likewise reduced, as compared with existing linings, becauseit is not necessary for the rubber rings to be bonded to the metal ofthe drum, since the lining can be located and maintained in position bythe end rings, as hereinafter described in greater detail.

In order to secure effective compression of the rubber rings, in thecase of a drum of any substantial length, the rods are formed ofsections,

adapted to be screwed together at joints located in the same transverseplane and a metal ring is provided at each joint plane, for holding inYcornpression the rubber rings mounted on the several rod sections.Preferably hook bolts, introduced through holes in the metal drum, areprovided, these embracing the rod sections and abutting against themetal rings to assist them in maintaining the rubber rings incompression. The metal rings and hook bolts also serve to conduct heatfrom the rubber lining to the exterior of the drum.

2v Claims. (o1. zar-182) Onespecic embodiment of the invention. will nowbe described in greater detail.. by Way of example, with reference tothe accompanying draw'mgs, in which Fig. l isa side elevation, partly insection, ci a ball mill tumbler drum fitted with a lining accord:- ingto the invention.

Fis. 2 is an enlarged part vertical. section thlfuell the drum,

Fig.. lv is a section on the line Ilmlll in Eig.r v2,

Fig. l is an enlarged section on the line lV--IV in Fig, 1,

Fig,v 5 is a section on the line V-V in Fig. fl, and

Fig. 6 is a detail sectional View showing the. attachment of the cuterend of one of' thestifiening bars to the left-hand end ring.

The tumbler drumhas a cylindrical metal body I0, to which are iitted endplates il, l2 carrying trunnions I3, lil. The left-hand end nlatell ispermanentlyy secured to the body` lc, as by welding, while theright-hand end plate l2 is .removable, being detachably secured by nut,and bolt connections I5 to an angle section ring 46 welded to theright-hand end ofthe body tu.

The lining for the body I0 c f the drum consists oi a plurality ofrubber rings I5 held in compression within the drum. but notvbonded tothe ,inner surface thereoi. These rings are threaded on to a pluralityof longitudinally extending steel rods, ci which there are twentyfsix inall, spaced at equal interval-s around the inner periphery of the drum.Each rod is built up of a number of sections Il. each having at one enda screwthreaded shank I8 and at the other a screw-threaded socket I9 foraccommodating the shank end of the adjoining section. The connectionsbetween the adjoining sections I 'l of all rods are located in commontransverse planes defined by metal rings 2!! which are located at these'positionsand serve to hold the rubber rings ifi on each set of rodsections l1 in compression when the rod sections are screwed together.

To introduce the lining, the right-hand end plate i2 is removed, and anend ring 12! of metal, drilled with holes which are afterwards tapped,is welded to the fixed end plate Il. Then a protective layer consistingof three rubber plies 22, 23, 24, and embodying sixteen equally spacedradially extending stiifening bars 25 is tted to the inner face of theend plate I l. A rubber filler element 225 is disposed between the bars25 and the ply 24. The rst set of rod sections II is then screwed intotapped holes 2G in the end ring 2|. The rod sections II at the top andbottom of the drum pass through holes 2'I at the outer ends of thevertically extending stiiening bars 25, one only of which is shown inFig. 2. The other stinening bars 25 are secured at their outer ends tothe end ring 2| by set screws 28 as shown in Fig. 6. At their inner endsthe stiffening bars 25 are secured to the end plate II by buried bolts29 and nuts 30.

After the required number of rubber rings IS (in the case illustratedtwenty-two) have been placed on the first set of rod sections I'I, thenext series of rod sections is screwed into the sockets I9 at the endsof the rst series, thereby causing a metal ring 20 placed over thethreaded Shanks I8 of the next series to compress the first set ofrubber rings I6. As indicated, the metal ring 20 is of greater internaldiameter than the rubber rings I so that it will be effectively enclosedwithin the rubber lining and protected from contact with orcontamination by the contents of the drum by reason of YVthe compressionof the rubber rings on either side of it.

Hooked ybolts 3| are introduced into position from -inside the drum toembrace the rod sections Il, these bolts projecting through apertures inthe drum IE! and being held in position by external nuts 32. The hookbolts contact the exposed surface of the metal ring and assist it tomaintain in compression the rubber rings I6 to the left of it.

A series of rubber rings I6 is then placed on the next series of rodsectionsl I, the first rubber ring H56 ci this next series being cutaway as shown to accommodate the hook bolts. This procedure of assemblyis followed until all the rod sections have been assembled, but the lastset of rod sections have threaded shanks IIS at their righthand ends inplace of sockets. A second metal end ring 33 is fitted over these shanks8 and held in position to lcompress the last set of rubber rings IB bynuts 34 :fitted to the shanks H8.

The removable end plate I2 is provided on its inner face with aprotective cover comprising three superposed plies |22, |23, |24 oirubber, and sixteen radially extending stiffening bars |25, with arubber ller element 325 between the bars and the ply |24, the stiieningbars being fixed to the end plate I2 by buried bolts |253 and nuts Atthe centre of the drum and at the top thereof in the positionillustrated is a rectangular loading and inspection aperture. At thislocality the topmost rod section II'I (Fig. 5) is interrupted and therubber rings I6 are cut away. At the transversely extending sides of theinspection aperture are located a pair of metal segments 44, one ofwhich only is shown in Figs. 4 and 5. These segments are supportedcentrally each on one end of the interrupted rod section II'I and heldthereto by a screw 35 introduced into a socket in the rod section, so asto keep in compression the rubber rings at either side of the aperture.The adjoining rod sections II pass through holes 36 near the extremitiesof the segments 34. The sides of the aperture are dened by a removablerectangular angle-section metal framework 31, which is inserted into thecutaway portion of the lining and rests on a saddle piece 38 welded tothe drum. The cover plug for the aperture is constituted by a metalplate, to which are secured by buried bolts 40 and nuts 4I three discs42 of rubber. The cover also carries a rubber skirt 43. By tighteningthe nuts 4I the rubber portion of the cover can be expanded into tightengagement with the sides of the aperture. The lower surface of thebottom rubber disc 42 of the cover plug mates up with the inner surfaceof the rubber lining when the plug is in position. The inner peripheryof the rubber rings is of sinuous form, the crests of the wave formationlying opposite the rods so that the effective thickness of the rubber iseverywhere the same as shown in Fig. 3. The bottom disc 42 of the coverplug is therefore of corresponding sinuous form as shown in Fig. 4.

Any desired type of rubber, either natural or synthetic, may be used inthe construction of the lining but I prefer to employ the material soldunder the Registered Trade Mark Linatex because of its especially highresistance to abrasion. This material is manufactured by the processdescribed in British Patent No. 437,928. Another form of rubber having ahigh degree of resistance to abrasion and particularly suitable for mypurpose is that made by the process described in U. S. Patent No.2,358,195.

Rubber linings constructed in accordance with the invention are alsosuitable for lining the tumbler drums of rotary washers or of concretemixing machines. In the latter case, the rubber will not only act toresist abrasion but also to reduce the tendency of the material to cake.Linings according to the invention may also be of use where the drum isto contain chemicals which corrode metal but do not attack rubber.

What I claim as my invention and desire to secure by Letters Patent is:

l. A rotary metal tumbler drum, having a removable rubber lining, saidlining comprising a plurality of circumferentially spaced longitudinallyextending rods, said rods being formed in sections screwed together atjoints located in common transeverse planes, a plurality of rubber ringsthreaded on said rods, a plurality of metal rings, each fitted to therods at one of the joint planes and having its inner edge shrouded bythe rubber, and end members for holding said rubber rings in axialcompression on said rods, said rod sections having cooperating spigotand socket ends arranged, when the rod sections are screwed together, tolocate said metal rings in position to hold in axial compression therubber rings disposed between each adjoining pair of metal rings.

2. A rotary tumbler drum, comprising a metal shell, a pair of end platesone of which is fixed and the other detachable from the shell, and aremovable rubber lining for the shell, said lining comprising aplurality of circumferentially spaced longitudinally extending rods,said rods being formed in sections screwed together at joints located incommon transverse planes and in screw threaded engagement with saidfixed end plate, a plurality of rubber rings threaded on said rods, aplurality of metal rings, each fitted to the rods at one of the jointplanes and having its inner edge shrouded by the rubber, and meansfitted to said rods at the ends thereof adjoining said detachable endplate for maintaining, in cooperation with said fixed end plate, saidrubber rings in axial compression on said rods, said rod sections havingcooperating spigot and socket ends arranged, when the rod sections arescrewed together, to locate said metal rings in position to hold inaxial compression the rubber rings disposed between each adjoining pairof metal rings.

FRANK MCINTYRE.

(References on following page) Number REFERENCES CITED 1,607,828 Thefollowing references are of record in the 1,921,672 file of this patent:2,058,257 UNITED STATES PATENTS I 357246 Number Name Date 151,338 AlsingMay 26, 1874 190,389 Irumbuu May 1, 18'1'1 Number 673,768 Fleming May 7,1901 1 251646 712,531 Hewlett Nov. 4, 1902 937,826 Lindhard Oct. 26,1909 1,120,108 Warwick Dec. 8, 1914 1,553,328 Roubal Sept. 15, 19251,601,956 Gammeter Oct. 5, 1926 Name Date Holthoi Nov. 23, 1926Haushalter Aug. 8, 1933 Porteous Oct. 20, 1936 Whitmyer Aug. 29, 1944FOREIGN PATENTS Country Date Italy Sept. 25, 1925 OTHER REFERENCESEngineering and Mining Journal-Press, Sept. 1924, v01. 118, No. 12, page476, McGraw-Hill Co. Inc., 10th Ave. at 36th St., New York City.

